1. Field of the Invention
The present invention relates to valve elements and, more particularly, to lightweight valve elements having reinforced sealing sections.
2. Description of the Background
Valve elements are found in many pumping mechanisms to control the direction of fluid flow through the pump. The valve element is typically biased to prevent fluid flow by sealing an annular valve seat during one portion of the pumping cycle. The valve element opens with respect to the valve seat to permit fluid flow during another portion of the pumping cycle.
Many deleterious forces act on the valve elements to cause a breakdown in the pump mechanism. For instance, in oil field mud and service pumps, valve elements may encounter reactive liquids at high pressures and temperatures. The liquids pumped in oil field applications include slurries containing various particulates and debris from the well bore that may damage the valve. Such liquids may have a wide range of viscosities. In some cases, highly caustic or acidic liquids may be pumped past the valve element that may score or damage parts of the valve element.
For this reason, most general service valve elements used in oil field pumps in the past have been comprised either substantially or completely of metal. However, the use of substantial amounts of metal in construction of the valve element used in such pumps results in a relatively heavy valve element. A heavy valve element produces a hammering effect each time it engages the valve seat. The excessive pounding of the valve element against the valve seat limits the lifetime of the valve element and the valve seat.
Lighter weight all-plastic valve elements, made of castable type resins of different hardness, have been used to make up the upper guide, body, and lower guide of the valve element (see for example U.S. Pat. No. 5,062,457). These valve elements suffer from the disadvantage that they must be made of compatible castable resins. Accordingly, such valve elements may suffer when the fluid media is not compatible with the castable resins used.
Consequently, there remains the need for an improved lightweight valve element that offers greater reliability and dependability of operation at reduced levels of capital investment.